Also, macrubyc will generate by default executables linking against MacRuby.framework dynamically, which greatly reduces the executable size. In order to build a full standalone executable, the —static argument must be passed.

Writing a standalone, self contained application gets easier with a new tool:

A new utility, called macruby_deploy, is now available to help you deploy your MacRuby applications. It provides options to compile ahead-of-time your application’s Ruby source code as well as relocating the MacRuby framework inside the application bundle. This way your application is ready for deployment, with its source code hidden because it is pre-compiled.

One addition is the QueryAgent which might become useful in the future to connect to a live system. It's a system that runs inside the Rubinius VM and waits for connections on a configurable port. Clients can connect to it and query certain status or runtime information; at the moment only configuration items seem to be available. The system uses BERT to encode the data sent across the connection. To try out the system, launch Rubinius with /bin/rbx -Xagent.port=$PORT_NUMBER (choose an available $PORT_NUMBER). The protocol is undocumented, but the Agent implementation gives a clue as to what's supported.

To try Rubinius, get the Rubinius 0.13 from Github. To compile, run ./configure followed by rake; to build Rubinius with LLVM replace ./configure with ./configure --enable-llvm which will take care of getting and building LLVM.
To see how Rubinius stacks up against Ruby 1.8.7, try out ./bin/bm to run a whole batch of benchmarks against MRI and then Rubinius.